5、数据库驱动与建表

Laravel 构建的实在是太友好，不懂数据库也可以进行开发。在前文中我们已经把数据库驱动改成使用 MySQL 了，并执行了迁移文件， 因此，关于更改数据驱动，就不在过多介绍了。

创建分类表迁移文件

我们的文章一般都有分类，现在，我们通过迁移文件来创建数据表吧。

使用 php artisan make:migration 命令可以创建对应数据表的迁移文件。

1、创建迁移文件

$ php artisan make:migration "create categorites table"

   INFO  Migration [database/migrations/2024_04_04_231218_create_categorites_table.php] created successfully.

该命令会在 database/migrations 目录生成对应的迁移文件。

2、修改迁移文件

<?php

use Illuminate\Database\Migrations\Migration;
use Illuminate\Database\Schema\Blueprint;
use Illuminate\Support\Facades\Schema;

return new class extends Migration
{
    public function up(): void
    {
        Schema::create('categories', function (Blueprint $table) {
            $table->id();
            $table->string('name')->comment('分类名');
            $table->timestamps();
        });
    }

    public function down(): void
    {
        Schema::dropIfExists('categories');
    }
};

3、执行迁移文件生成数据表

$ php artisan migrate

   INFO  Running migrations.  

  2024_04_04_231218_create_categorites_table ..................................................................... 57.63ms DONE

查看表结构

迁移文件是如何记录的？我们可以通过命令进行查看

$ php artisan db:table

 ┌ Which table would you like to inspect? ──────────────────────┐
 │ migrations                                                   │
 └──────────────────────────────────────────────────────────────┘


  migrations ..................................................................................................................  
  Columns ................................................................................................................... 3  
  Size ............................................................................................................... 16.00 KB  

  Column ................................................................................................................. Type  
  id int, autoincrement .......................................................................................... int unsigned  
  migration varchar, utf8mb4_unicode_ci .......................................................................... varchar(255)  
  batch int ............................................................................................................... int  

  Index .......................................................................................................................  
  primary id ................................................................................................... btree, primary 

回滚迁移文件

你应该注意到迁移文件中有两个方法：up 和 down。其中，up 用来生成数据表，而down 则是用户回滚操作。

php artisan migrate:rollback

rollback 命令将仅回滚最后一批迁移。

查看数据表

$ php artisan db:show

  MySQL ................................................................................................................ 8.0.30  
  Database ................................................................................................ book_laravel11_blog  
  Host .............................................................................................................. 127.0.0.1  
  Port ................................................................................................................... 3306  
  Username ............................................................................................................... root  
  URL .........................................................................................................................  
  Open Connections .......................................................................................................... 4  
  Tables ................................................................................................................... 10  
  Total Size ........................................................................................................ 160.00 KB  

  Table .................................................................................................................. Size  
  cache .............................................................................................................. 16.00 KB  
  cache_locks ........................................................................................................ 16.00 KB  
  categories ......................................................................................................... 16.00 KB  
  failed_jobs ........................................................................................................ 16.00 KB  
  job_batches ........................................................................................................ 16.00 KB  
  jobs ............................................................................................................... 16.00 KB  
  migrations ......................................................................................................... 16.00 KB  
  password_reset_tokens .............................................................................................. 16.00 KB  
  sessions ........................................................................................................... 16.00 KB  
  users .............................................................................................................. 16.00 KB